Because the uplink in a Wideband Code Division Multiple Access (WCDMA) cellular radio system is non-orthogonal the so called near-far problem must be handled, i.e. a terminal close to the base station could easily drown the signal from a terminal at the cell border. To ensure the coverage of terminals at the cell border a limit is introduced on the total received power at the base station. A relative measure of total interference is rise over thermal (RoT) or noise rise, i.e. total interference relative to thermal noise, see Harri Holma, Antti Toskala, “WCDMA for UMTS—Radio Access For Third Generation Mobile Communications”, third Edition.
The uplink total interference may come from both intra-cell interference and inter-cell interference. In order to be able to control the RoT a cell should estimate the level of inter-cell cell interference it is currently experiencing.
Load control is a functionality used for WCDMA uplink. Load control determines for each cell the maximum available load room that can be used by the scheduling function based on the uplink interference situation in that cell, see Harri Holma, Antti Toskala, “WCDMA for UMTS—Radio Access For Third Generation Mobile Communications”, third Edition.
There are many different options to implement load control. Below two different exemplary implementations are described.
In a first example all the load which originates from users who are not served by one cell is treated (and estimated) in a single term called Lother, where Lother is caused by the inter cell interference. The load available Lavail for the scheduler of one in the cell is then calculated as:Lavail=Lmax−Lother   (1)
Where Lmax is the maximum allowed load in one cell, which is determined by the target (or maximum allowed) RoT in that cell. Lavail is the load available for said cell (own cell available load room). The total load in the cell can be said to be Lavail (if it is used) plus Lother, hence, this will be referred to as the two term approach.
In a second example the fact that transmissions stemming from User Equipments (UEs) who are not served but in soft handover (SHO) with said one cell are received and decoded by that cell is used. Since the transmission is received, the load of the transmission can be calculated. With this information the available load is calculated as:Lavail=Lmax−LSHO−Lother   (2)
i.e. the available load is equal to the maximum load in that cell, minus the load stemming from UEs in SHO with that cell but have some other cell as serving cell (LSHO), minus the load from all the other UEs (Lother), where Lother is caused by the inter cell interference. This is referred to as the three term approach. Thus, in the three term approach the load caused by UEs in SHO are separated from the inter cell interference.
There is a desire for new methods and devices providing improved estimation of the available load for a cell in a cellular radio system, in particular a WCDMA system in order to improve the load scheduling in the cells of the cellular radio system.